Neuropathology of the basal ganglia, in particular, of the mesolimbic dopamine system the strongest viable theory in the study of neurochemical correlates of schizophrenia. The ventral striatum has figured prominently in this theory. This striatal region has long been known to receive afferents from limbic structures. A number of segregated circuits, including one associated with the limbic system, have been shown to funnel information through the basal ganglia. These systems, arising from functionally identified cortical areas, pass through the basal ganglia, and via the thalamus project back to cortical regions subserving the original function. The one best characterized is the motor circuit. Little is known concerning the continuity of the limbic circuit The studies proposed here are intended to identify the extent to which the output limbic pathways of the basal ganglia via the globus pallidus maintain continuity with the limbic system via specific c and midbrain regions that in turn project to limbic-related cortical areas. Elucidating how limbic pathways are funneled through the basal ganglia will lead to a more comprehensive understanding of how this circuit contributes to the constellation of clinical symptoms seen in diseases affecting the basal ganglia. Using electrophysiological mapping methods, anterograde and retrograde tracers will be placed into the output pathways of the limbic-related globus pallidus to chart its projections to and midbrain regions. The relationship between the regions of the thalamus and midbrain, (in particular the subthalamic n.) that receive these terminals and their projections to limbic-related cortical areas is a the major focus of this proposal.